1. Field of the Invention
The present invention relates generally to an apparatus and a method employed in manufacture of semiconductor modules. More particularly, the present invention relates to automatically loading or unloading multiple printed circuit boards into or from a jig carrier during a process of manufacturing semiconductor modules.
2. Description of the Prior Art
As electronic devices become more complex and employ more integrated circuits, it is desirable, if possible, to avoid increasing the space they occupy. To solve this problem, modules mounted with multiple integrated circuit devices have been employed. In a typical module, the integrated circuit devices, for example, semiconductor packages, are attached to either one side of a printed circuit board (PCB) in case of a single-sided module or both sides of PCB in case of a double-sided module.
For higher productivity, modules are generally produced in a production line where PCBs move along conveyor belt. In particular, sheet-type PCBs are subjected to module manufacturing processes that are well known in the art. In such processes, each sheet-type PCB has a number of individual PCBs, what are called piece-type PCBs, which are linked with each other at their ends, leaving space between adjacent individual PCBs. Final modules, each including a single individual PCB, are obtained by cutting the link parts of the sheet-type PCBs after completing the process.
However, the use of the sheet-type PCBs raises some problems. One problem is that the sheet-type PCBs include wasted parts, such as link parts or space. These wasted parts are required during the manufacturing process, but not required in the final product. Moreover, although unexpected failure may be found among the individual PCBs composing one sheet-type PCB during the manufacturing process, the failed PCBs are subjected to the final steps of the process because of the difficulty in removing the failed PCBs. This can significantly reduce productivity.
Accordingly, in recent years, individual PCBs without the link part or space are separated at the beginning of the module manufacturing process. This can reduce the per the unit cost of modules because the absence of the link part or space reduces the required amount of raw PCB materials. A jig carrier makes this improvement possible. That is to say, the jig carrier can not only carry a large number of individual PCBs, but also provides better productivity than the sheet-type PCB processes.
FIG. 1 is a perspective view of a jig carrier 10 as a conventional apparatus for carrying PCBs 20 for semiconductor modules; and FIG. 2 is a perspective view for schematically showing a typical PCB 20 for a semiconductor module.
As shown in FIGS. 1 and 2, the known jig carrier 10 comprises a rectangular frame 12 and two opposite plates 14 inside the frame 12. Pins 6 are formed at regular intervals on the plates 14. The PCB 20 is a rectangular panel having two opposite shorter edges 21 and two opposite longer edges 22. The PCB 20 includes a number of circuit patterns, not shown, formed on both top and bottom surfaces thereof, as widely known in the art. The PCB 20 further comprises through holes 26 corresponding to the pins 16 of the jig carrier 10.
When the PCB 20 is loaded in the jig carrier 10, the plates 14 of the jig carrier 10 support the bottom surface of the PCB 20, and the pins 16 are inserted into the through holes 26. After all PCBs 20 are loaded into the jig carrier 10, adhesive tape 18 is stuck to both top surfaces of the PCB 20 and the jig carrier 10, so that the PCB 20 is fixed to the jig carrier 10.
A disadvantage of the existing jig carrier 10 is that attaching the tape 18 and the loading of the PCBs 20 are done manually. In addition, in case of the double-sided module, the adhesive tape 18 must be removed from the PCBs 20 and the PCBs 20 are flipped over in the jig carrier 10 for attachment of other devices onto the back side of the PCB 20. The required manual manipulations reduce the productivity of the module manufacturing process. Additionally, different kinds and sizes of PCBs 20 are employed in different modules. The different PCBs 20 require different jig carriers 10. Thus, the use of a jig carrier 10 is limited by the size of its frame 12 and the position of its pins 16.